Manure spreaders of the slurry type generally include a tank for containing manure with an auger rotatably mounted in the bottom of the tank for moving manure toward an opening formed in a sidewall of the tank. An expeller is disposed at the opening in the sidewall of the tank to discharge manure in a generally lateral direction from the spreader.
Power devices such as hydraulic cylinders have been provided in slurry type manure spreaders for raising the auger in the tank to break up manure that bridges above the auger and to break the auger out of manure that is frozen in the bottom of the tank. In one prior slurry spreader, hydraulic cylinders were utilized for raising the auger but not for lowering it, and the auger was permitted to move upward by itself independently of the hydraulic cylinders to clear obstructions such as rocks which become lodged between the auger and the bottom wall and the sidewalls of the tank. A problem existed with this one prior slurry spreader in that whenever the auger moved upward by itself independently of the hydraulic cylinders, the auger often would not return to its normal position in the tank quickly enough to keep a steady flow of manure moving toward the expeller. Another problem was that the auger, due to its natural buoyancy, tended to float upward at inappropriate times.
The present invention overcomes this problem by providing resilient means for constantly urging the auger downwardly in the tank. The resilient means is designed to allow the auger to be raised by power devices or to move upward by itself independently of the power devices. The resilient means acts to quickly return the auger to its normal position after being raised by the power devices or after moving upward by itself. In the preferred embodiment of the present invention, the resilient means comprises springs connected to the auger.